1. Field of the Invention
This invention broadly relates to an appliance that is used in the course of orthodontic treatment. More particularly, the present invention relates to an orthodontic bracket with an attachment such as a latch, hook or other type of component.
2. Description of the Related Art
Orthodontic treatment involves movement of malpositioned teeth to desired locations along the dental arch. Orthodontic treatment can greatly enhance the patient""s appearance once the teeth are moved to desired locations in the oral cavity. In addition, orthodontic treatment can improve the patient""s occlusion so that the teeth of one jaw function in a satisfactory manner in combination with the teeth of the opposing jaw.
A variety of orthodontic treatments are known in the art. In one type of treatment, a set of tiny slotted appliances known as brackets are fixed to the patient""s teeth and an archwire is then placed in the slots of the brackets. Ends of the archwire are often received in a special type of bracket known as a buccal tube that is fixed to the patient""s molar teeth. The archwire has an overall xe2x80x9cUxe2x80x9d-shaped configuration and forms a track to guide movement of the teeth to desired locations along the dental arch.
Orthodontic brackets are widely available in a number of different configurations and constructed of different materials. Many brackets are made of metallic materials such as stainless steel. Stainless steel brackets are relatively inexpensive and yet sufficiently strong to precisely control movement of the teeth to desired locations.
Other types of orthodontic brackets are made of transparent or translucent materials such as plastic or ceramic. These types of brackets are more difficult to see in the oral cavity when worn by the patient and consequently are considered more aesthetic than metal brackets. Examples of aesthetic ceramic and plastic brackets are described in U.S. Pat. Nos. 4,954,080, 5,439,379 and 5,522,725.
A variety of manufacturing methods are known for making orthodontic brackets, and are often selected based in part upon the choice of materials for the bracket. Stainless steel brackets, for example, are often machined using an automated rotary mill. An example of a method for making orthodontic brackets using a ring milling technique is described in U.S. Pat. No. 2,713,720.
Stainless steel brackets can also be manufactured using a casting technique or a metal injection molding technique. In the casting technique, a quantity of metal heated to a melting temperature is directed into a mold cavity and allowed to cool and harden. In a metal injection molding technique, a quantity of metallic powder along with a binder is forced under pressure into a mold cavity, and the mold is heated until such time as the metal particles have sintered together to form a dense, unified body.
Plastic and ceramic brackets may also be made using different techniques. For example, ceramic brackets and brackets made of relatively hard plastic can be machined to a desired configuration. Alternatively, brackets that are made of some plastic or ceramic materials can be made using a dry pressing technique or an injection molding technique.
Typically, orthodontic brackets have an overall size that is relatively small. More specifically, most orthodontic brackets have overall dimensions that are less than 0.25 inch (6 mm) on each side. As a consequence, it has often been attempted to make orthodontic brackets in one piece as a single, unitary component or at most in two initially separate pieces in order to avoid the necessity of making and assembling several small, separate components.
However, some brackets are provided with attachments that serve particular functions. For example, certain brackets are provided with outwardly extending elongated attachments known as hooks. Hooks are sometimes used by orthodontists during the course of treatment to receive one end of an elastic member, the other end of which is connected to a hook that is attached to another bracket in the oral cavity. The elastic member exerts a force in tension that tends to urge the inter-connected brackets and consequently the associated teeth toward each other.
In the past, other brackets with hooks have been made as an initial single component, by milling or by molding the hook directly to another portion of the bracket. An example of a bracket with an integral hook is described in U.S. Pat. No. 5,395,237. As an alternative, other metal brackets with hooks have been made by brazing or welding a hook to a portion of the bracket. In either instance, it is important to ensure that the resulting connection between the hook and the bracket is secure so that the hook does not detach from remaining portions of the bracket during the course of treatment.
Other types of bracket attachments are also known. For example, some brackets include a movable clip for holding an archwire in the archwire slot of the bracket. Examples of such brackets are described in U.S. Pat. Nos. 4,197,642, 4,698,016, 5,322,435 and 6,168,428 and are often called xe2x80x9cself-ligatingxe2x80x9d brackets.
While the brackets described above have been generally satisfactory, there is a continuing interest in the art to improve manufacturing methods for orthodontic brackets, especially orthodontic brackets with attachments. Preferably, any improved manufacturing methods and the resulting brackets would not unduly increase the overall size of the bracket so that the likelihood of patient discomfort need not be increased.
The present invention is directed toward an orthodontic bracket having one or more cavities for receiving an attachment. The cavities are located in tiewings of the bracket and consequently occupy a region of the bracket that might otherwise be unused. The cavities provide a convenient mounting location for supporting the attachments in a prominent location, such as in an area near the front of the bracket where the attachment may be best utilized.
Advantageously, the cavities provide a useful and inexpensive means for connecting the attachment to remaining portions of the bracket without necessarily increasing the overall size of the bracket. As such, there is less likelihood that the bracket will protrude into adjacent soft tissue in the oral cavity and cause discomfort to the patient. In addition, by avoiding an increase in the overall size of the bracket, the visibility of the bracket when worn by the patient is not increased and the aesthetic appearance of the bracket in the oral cavity need not be adversely affected.
In more detail, the present invention in one aspect concerns an orthodontic bracket that comprises a first body having a trunk portion, an occlusal tiewing portion, a gingival tiewing portion and an archwire slot portion extending between the occlusal tiewing portion and the gingival tiewing portion. The orthodontic bracket also includes a second body having a trunk portion, an occlusal tiewing portion, a gingival tiewing portion and an archwire slot portion extending between the occlusal tiewing portion and the gingival portion. The first body and the second body are located adjacent each other such that the occlusal tiewing portion of the first body and the occlusal tiewing portion of the second body present a single occlusal tiewing, and the gingival tiewing portion of the first body and the gingival tiewing portion of the second body present a single gingival tiewing.
Another aspect of the present invention is also directed toward an orthodontic bracket. In this aspect, the bracket comprises a first body having a trunk portion, an occlusal tiewing portion, a gingival tiewing portion and an archwire slot portion extending between the occlusal tiewing portion and the gingival tiewing portion. The bracket also includes a second body having a trunk portion, and occlusal tiewing portion, a gingival tiewing portion and an archwire slot portion extending between the occlusal tiewing portion and the gingival tiewing portion. The first body and the second body are located adjacent each other such that the occlusal tiewing portion of the first body and the occlusal tiewing portion of the second body present a single occlusal tiewing, and the gingival tiewing portion of the first body and the gingival tiewing portion of the second body present a single gingival tiewing. The occlusal tiewing portions have outer occlusal tips that engage each other, and the gingival tiewing portions have outer gingival tips that engage each other. A cavity is located between the first body and the second body, and a latch is located at least partially in the cavity for retaining an archwire in the archwire slot.
The present invention is also directed in another aspect to an orthodontic bracket. In this aspect, the bracket includes a base and a body extending outwardly from the base. The body includes an occlusal tiewing, a gingival tiewing, and an archwire slot extending between the occlusal tiewing and the gingival tiewing. The body includes a cavity that extends along occlusal, gingival and lingual sides of the archwire slot. A latch is located at least partially in the cavity for retaining an archwire in the archwire slot.
The present invention is also directed in another aspect to an orthodontic bracket. In this aspect, the bracket includes a first body having a trunk portion, an occlusal tiewing portion and a gingival tiewing portion. The bracket also includes a second body having a trunk portion, an occlusal tiewing portion and a gingival tiewing portion. The first body and the second body are located adjacent each other such that the occlusal tiewing portion of the first body and the occlusal tiewing portion of the second body present a single occlusal tiewing, and the gingival tiewing portion of the first body and the gingival tiewing portion of the second body present a single gingival tiewing. A cavity is located between the first body and the second body. A latch is located at least partially in the cavity for retaining an archwire in the archwire slot.
The present invention is also directed in another aspect to a method of making an orthodontic bracket. In this aspect, the method includes the act of providing a first body having a mesial side and the act of providing a second body having a distal side. The first body is connected to the second body such that the distal side of the second body contacts the mesial side of the first body. A cavity is established between the mesial side of the first body and the distal side of the second body. An attachment is placed in a position at least partially in the cavity.
Another aspect of the invention is directed toward a method of making an orthodontic bracket. The method includes the act of providing a first body having a trunk portion, an occlusal tiewing portion, a gingival tiewing portion and an archwire slot portion extending between the occlusal tiewing portion and the gingival tiewing portion. The method also includes the act of providing a second body having a trunk portion, an occlusal tiewing portion, a gingival tiewing portion and an archwire slot portion extending between the occlusal tiewing portion and the gingival tiewing portion. The method further includes the act of assembling the first body to the second body such that the occlusal tiewing portion of the first body contacts the occlusal tiewing portion of the second body and the gingival tiewing portion of the first body contacts the gingival tiewing portion of the second body.
An additional aspect of the present invention is also directed toward a method of making an orthodontic bracket. This method includes the act of providing a first body having a trunk portion, an occlusal tiewing portion, a gingival tiewing portion and an archwire slot portion extending between the occlusal tiewing portion and the gingival tiewing portion. The method also includes the act of providing a second body having a trunk portion, and occlusal tiewing portion, a gingival tiewing portion and an archwire slot portion extending between the occlusal tiewing portion and the gingival tiewing portion. The method further includes the act of assembling the first body to the second body such that the occlusal tiewing portion of the first body is adjacent the occlusal tiewing portion of the second body and together present a single occlusal tiewing and a gingival tiewing portion of the first body is adjacent a gingival tiewing portion of the second body and together present a single gingival tiewing.
Other aspects of the invention are described in the detailed description set out below and are illustrated in the accompanying drawings.